sell off vs selloff

sell off is not a noun while selloff is a noun.

Word	Noun	Adjective	Verb	Adverb
sell off	No	No	Yes	No
selloff	Yes	No	No	No

sell off (noun)	selloff (noun)
	a sale of a relatively large number of assets (stocks or bonds or commodities) at a low price typically done to dispose of them rather than as normal trade

sell off (verb)	selloff (verb)
get rid of by selling, usually at reduced prices